Bariatrics, a branch of medicine which deals with the treatment of obesity, has become increasingly important as the prevalence of obesity has been increasing for two decades and continues to rise.
PCT Publication WO 06/035446 to Karasik, which is incorporated herein by reference, describes an apparatus and a method for treating a weight disorder in a subject. The apparatus comprises an implantable device such as an inflatable balloon and electrodes capable of sensing a physiological change associated with food ingestion or hunger and a mechanism adapted for directly stimulating a region such as the duodenum which is responsive to a gastrointestinal satiety agent. Such a mechanism can be a drug reservoir containing a drug such as CCK or analogs thereof which is contained within an inflatable balloon being implantable in a stomach of the subject. The apparatus and method provided are described as combining synergistic approaches to limiting meal size, i.e., chemo and mechano receptor activation of vagal satiety stimuli, electric stimulation of specific vagal pathways and limitations of gastric space.
U.S. Pat. No. 6,115,635 to Bourgeois, which is incorporated herein by reference, describes a method and apparatus for providing electrical stimulation of the gastrointestinal tract. The apparatus features an implantable pulse generator which may be coupled to the gastric system through one or more medical electrical leads. In the preferred embodiment the leads couple to the circular layer of the stomach. The pulse generator preferably features sensors for sensing gastric electrical activity, and in particular, whether peristaltic contractions are occurring. One embodiment is described as particularly solving the problem of accurately detecting gastric arrhythmias by periodically reverting into a sensed intrinsic gastric rhythm mode. In this mode the output of electrical stimulation is adjusted to only occur at an exceedingly slow rate. This slow rate of stimulation thus permits the gastro-intestinal tissues to undergo an intrinsic depolarization so that the underlying intrinsic slow wave rate may be detected.
U.S. Pat. No. 7,043,295 to Starkebaum, which is incorporated herein by reference, describes methods and systems for treating patients suffering from eating disorders, e.g. obesity, through the dispensation of a drug by an implantable infusion pump delivering drug into the cerebral spinal fluid (CSF) at a site of the intrathecal space in amounts and at times effective to suppress the patient's appetite through interaction of the drug transported through the CSF with receptors in the brain. Delivery of a programmed drug dosage is preferably at a programmed time (or at programmed times) of day, in response to a command received from the patient, or in response to a trigger signal developed from a sensed GI tract signal accompanying peristalsis.
US Patent Application Publication 2003/0144708 to Starkebaum, which is incorporated herein by reference, describes methods and systems for treating patients suffering from eating disorders, e.g. obesity, through the delivery of electrical stimulation directly or indirectly to the pylorus of a patient in an effective stimulation regimen to substantially close the pylorus lumen to inhibit emptying of the stomach. The stimulation electrodes are applied directly to or immediately adjacent to the muscle layers of the pyloric sphincter, or are situated in operative relation to the splanchnic nerve that innervates the pyloric sphincter. Stimulation can be delivered continuously 24 hours per day, or can be halted at meal times to enable passage of chyme through the pylorus lumen at such times. Alternatively, stimulation is described as being delivered following events related to peristalsis, ingestion or stomach emptying, to induce a feeling of satiety.
An article entitled “Effect of feeding on the activity of duodenal smooth muscle in dogs,” by Shemerovskii, Biull Eksp Biol Med. 1978 October; 86(10):394-7, which is incorporated herein by reference, describes an investigation into the electric activity of the duodenum smooth muscles with chronically implanted electrodes. This activity after feeding was compared with that in fasting during the time equal to the period of rest and the active period of the duodenum in fasting. The number of pacesetter potentials was identical during digestion and fasting. The number of spike potentials was significantly different during these compared states. The relationship of the “digestive” and “hungry” electrical activities of the duodenum depended both on the compared type of potential and on the compared time periods.
PCT Application WO 06/102626 to Policker et al., which is incorporated herein by reference, describes apparatus including a control unit, adapted to be implanted within a patient, and a corkscrew-shaped electrode mount, adapted to be implanted in a wall of a stomach of the patient. The corkscrew-shaped electrode mount includes first and second electrodes, at respective sites of the electrode mount, and a controller, wirelessly coupled to the control unit. Other embodiments are also described.
An article entitled “Small Bowel Motility Affects Glucose Absorption in a Healthy Man” by Schwartz, Diabetes Care, Volume 25, Number 10, October 2002, which is incorporated herein by reference, describes an investigation into the relationship between duodenojejunal motor activity and glucose absorption and an evaluation of the effect of modification of duodenojejunal motility on glucose absorption by using the prokinetic drug cisapride. The main findings of the study are described as being that, in healthy subjects, an increase in number of duodenojejunal pressure waves and antegrade propagated pressure waves was related to an increase in small intestinal glucose absorption; treatment with cisapride increased the mean amplitude of duodenojejunal pressure waves, but did not affect the number of pressure waves and spatiotemporal organization of antegrade propagated pressure waves and cisapride treatment did not affect glucose absorption.
An article entitled “The electrical activity of the digestive tract of the sheep as an indication of the mechanical events in various regions,” by Rukebusch, J. Physiol. (1970), 210, pp. 857-882, which is incorporated herein by reference, describes a method used in conscious sheep for recording oscillographically the electrical potentials led from enamelled stainless-steel wires implanted in the wall of the stomach and intestine. Slow waves characterized by cyclically recurring and rhythmic fluctuations in voltage were described as having been recorded, together with the superimposed fast activity or burst of spikes when the muscle is contracting. The whole activity is described as comprising a distinguishable pattern of grouped discharge which is synchronous with mechanical events within different regions of the alimentary tract. The relationship between electrical and mechanical activity of the reticulo-rumenal movements was examined at rest, and during feeding and ruminating. Electrical correlates of motor activity in the small bowel were investigated under different dietary regimens.
An article entitled “Rate of flow of digesta and electrical activity of the small intestine in dogs and sheep,” by Bueno, J Physiol. (1975), 249, pp. 69-85, which is incorporated herein by reference, describes experiments that were undertaken on dogs and sheep (i) to investigate the relation between the migrating myoelectric complex and the rate of passage of digesta along the small intestine; (ii) to analyze the influence of the irregular spiking phase and of the regular spiking phase on the mean velocity of the intestinal contents; (iii) to emphasize the function of the migrating myoelectric complex as a permanent moving process which regulates the flow of intestinal contents. It concludes that in the fasted dog and in the sheep, the migrating myoelectric complex controls the pressure gradients on which the flow of intestinal contents depends. This is accomplished in the main by the prolonged phase of irregular spiking activity, and it is suggested that the regular spiking activity which follows it, though not in itself propulsive, serves as a barrier to prevent backflow of digesta into the quiescent part of the intestine. When continuous spiking activity is induced, by feeding in the dog and by injection of 5-hydroxytryptophan in the sheep, no part of the intestine is quiescent and the transit time is shortened by the incessant irregular spiking activity.
An article entitled “Relationships between electrical activities of antrum and duodenum,” by Allen, Am. J. Physiol. 207(4): 906-910, 1964, which is incorporated herein by reference, describes a study that attempted to determine whether the slow basic electrical rhythms of the antrum and the duodenum were related, and to search for relationships between the fast electrical activities of the two regions. Observations were made on five healthy, trained, unanaesthetized dogs by means of detecting electrodes surgically implanted on the walls of the antrum and duodenum. No relationship was found, in either fasted or fed dogs, between the slow electrical rhythms of the antrum and duodenum. Feeding increased the fast activity in the antrum and in the duodenum, and under these circumstances, the fast activity in the duodenum was related to the slow basic electrical rhythm of the antrum.
The following patents and patent applications, which are incorporated herein by reference, may be of interest:    U.S. Pat. No. 7,076,306 to Marchal et al.    U.S. Pat. No. 7,076,305 to Imran et al.    U.S. Pat. No. 7,054,690 to Imran    U.S. Pat. No. 7,004,965 to Gross    U.S. Pat. No. 6,853,862 to Marchal et al.    U.S. Pat. No. 6,591,137 to Fischell et al.    U.S. Pat. No. 6,579,301 to Bales et al.    U.S. Pat. No. 6,571,127 to Ben-Haim et al.    U.S. Pat. No. 6,535,764 to Imran et al.    U.S. Pat. No. 6,104,955 to Bourgeois    U.S. Pat. No. 5,995,872 to Bourgeois    U.S. Pat. No. 5,861,014 to Familoni    U.S. Pat. No. 5,836,994 to Bourgeois    U.S. Pat. No. 5,813,993 to Kaplan et al.    U.S. Pat. No. 5,540,730 to Terry et al.    European Patent 0,129,483 to Shturman et al.    US Patent Application Publication 2006/0173238 to Starkebaum    US Patent Application Publication 2006/0142803 to Mintchev    US Patent Application Publication 2005/0222638 to Foley et al.    US Patent Application Publication 2005/0090873 to Imran    US Patent Application Publication 2004/0176685 to Takizawa et al.    US Patent Application Publication 2004/0172088 to Knudson et al.    US Patent Application Publication 2004/0167583 to Knudson et al.    US Patent Application Publication 2004/0107004 to Levine et al.    US Patent Application Publication 2004/0059393 to Policker et al.    US Patent Application Publication 2004/0044376 to Flesler et al.    US Patent Application Publication 2003/0208212 to Cigaina    US Patent Application Publication 2003/0181958 to Dobak III    US Patent Application Publication 2003/0066536 to Forsell    US Patent Application Publication 2001/0011543 to Forsell    PCT Application WO 06/118790 to Maschino et al.    PCT Application WO 05/041749 to Imran    PCT Application WO 04/112563 to Ben-Haim et al.    PCT Publication WO 04/078252 to Karashurov    PCT Publication WO 04/043280 to Utley et al.
The following articles, which are incorporated herein by reference, may be of interest:    Jean-Marie Calmes et al., “Laparoscopic Gastric Banding: A Prospective, Randomized Study Comparing the Lapband and the SAGB: Early Results CME,” Annals of Surgery (Mar. 2, 2005)    Yamada et al., “Effects of drugs on electromechanical activities of the stomach and duodenum of conscious dogs,” Nippon Heikatsukin Gakkai Zasshi. 1983 February; 19(1):25-35